Hybrid electric vehicles or electric vehicles are configured such that an appropriate voltage is supplied to an electric motor from a battery having a plurality of battery modules connected together in series or parallel.
As the battery is repeatedly charged and discharged, the temperature of the battery rises due to its internal resistance. Since the temperature rise of the battery has a significant influence on the performance and durability of the battery, the battery is maintained at a constant temperature by controlling an operation of a cooling fan.
An operating stage of the cooling fan is controlled on the basis of the temperature of inlet air to the battery and the maximum temperature of the battery modules. However, a sensor for measuring the inlet temperature has to be separately provided, which causes an increase in cost.
Furthermore, a separate evaluation process has to be conducted to examine the consistency of the sensing position of the inlet temperature sensor.